Megestrol in Treating Patients With Endometrial Neoplasia or Endometrial Hyperplasia

Inclusion Criteria: * Patients must have a diagnosis of atypical endometrial hyperplasia (AEH) or endometrial intraepithelial neoplasia (EIN) diagnosed by dilatation and curettage (D\&C), Novak curettage, Vabra aspirate, or Pipelle endometrial biopsy at the enrolling institution within 12 weeks of enrollment * Patients must desire uterine retention for duration of study (18 months or after 3rd biopsy) if they remain EIN negative (-); patients are allowed to attempt pregnancy after their initial post-treatment biopsy without it being a major protocol violation * Patients must have a GOG performance status of 0, 1, or 2 * White blood cell (WBC) \>= 3000 * Platelets \>= 100,000 * Granulocytes \>= 1,500 * Creatinine =\< 2 * Bilirubin =\< 1.5 x institutional upper limit normal * Serum glutamic oxaloacetic transaminase (SGOT) =\< 3 x institutional upper limit normal * Alkaline phosphatase =\< 3 x institutional upper limit normal * Patients of child-bearing potential must have a negative serum pregnancy test prior to starting study drug and prior to each biopsy if capable of becoming pregnant (and at the discretion of the referring physician) * Patients of childbearing potential must use appropriate non-hormonal contraception while on study medication * Patients who have met the pre-entry requirements * Patients must have signed an approved informed consent and authorization permitting release of personal health information Exclusion Criteria: * Patients with a GOG performance st…